Bevel protractor



Patented Nov. 6, 1962 lice 3,061,932 BEVEL PRUTRAC'IGR Edgar W. Ailen, Rte. 3, Eldon, Mo. Filed .iuiy 17, B59, Ser. No. 827,818 Saints. (Ci. 33- 24) This invention relates to an improved bevel protractor.

The primary object of the invention is to provide a simpler, more compact, and more versatile device of this kind which affords a greater number, than usual, of usable angle settings with fewer adjustments of the components of the device.

Another object of the invention is to provide a devlce of the character indicated above which is constituted by a smaller than usual number of simple parts, and which has simple and easily operated and more accurate locking means for locking the blade in lengthwise adjustments relative to the turntable, and for locking the turntable in rotary adjustments elative to the blade.

' Other important objects and advantageous features of the invention will be apparent from the following description andthe accompanying drawings, wherein, for purposes of illustration only, a specific form of the invention is set forth in detail.

In the drawings:

FIGURE 1 is a top plan view of a device of the invention;

FIGURE 2 is a transverse section taken on the line 22 of FIGURE 1; and FIGURE 3 is a longitudinal section taken on the line 33 of FIGURE 1. 7

Referring in detail to the drawings, wherein like numerals designate like parts throughout the several views, the illustrated device comprises a longitudinally elongated rigid blade 10 having opposed parallel straight edges 12 and 14, and parallel upper and lower sides 16 and 18, respectively, and a turntable 20 in which the blade 10 is slidably and rotatably mounted.

The turntable 2% comprises a flat protractor plate 22, substantially wider than the blade 19, and of mutilated triangular shape and has a straight base or transverse edge 24, a first straight edge 26 which is disposed at an angle of seventy-five degrees to the base edge, and a secoud straight edge 28 which is disposed at an angle of sixty degrees to the base edge. At the end of the plate 22 remote from the base edge 24, the apex portion of the plate 22 is formed with a notch 39 whose sides are disposed at an angle of ninety degrees to each other. The plate 22 has a free side 32 and a reverse side 34, and has on the free side, and aligned with the apex of and bisecting the notch 31 a base line 35.

The plate 22 is formed therethrough with a circular opening 36, of lar er diameter than the width of the blade 19, which is centered on the base line 35, and on its reverse side 34, with an annular groove 38 which indents the plate 22 and surrounds and opens into the opening 36. A circular block 40, larger in diameter than the opening 36, has a 'face side 42-bearing rotatably against the reverse side 34 or" the plate 22. On the face side of the block at) is a concentric, double-chamfered boss projection, providing a first circular boss 44 rotatably fitting and engaged in the opening 36, and a second circular boss 46, fitting and rotatably engaged in the groove 38.

Extending chordally through the block 49 and opening through its peripheral edge 48 is a slot 54 which has a depth of a half-diameter of the block and is of a Width not substantially greater than the thickness of the blade 10. The slot 50 has a bottom 52 which is on a diameter of the boss projection, and the blade It? extends lengthwise through the slot 5%, and is supported on the slot bottom 54 chordally across the block 40 for endwise sliding relative thereto. As seen in FIGURE 2, the face side 16 of the blade is formed with a longitudinal locking groove 62 which is parallel to and spaced from the blade edges. A blade locking screw 64 comprises a threaded shank 66 having on one end an offset pin 68 which extends between the face side of the blade 10 and the adjacent side of the slot 50 and terminates in a lateral detent 7%, which is engaged in the locking groove 62. The threaded shank 65 is exposed in an opening 72 provided through the block 40 at the bottom of the slot 5% and opening thereinto. Circumposed on the shank 65 and bearing against the side 74 of the opening 72 is a compression Washer '76, and a knurled locking nut 73 is threaded on the slant against the washer, and which, when tightened on the shank, draws the blade it? against the bottom 52 of the slot 55 so as to frictionally lock the blade 10 in a selected endwise adjustment relative to the turntable 29. The blade It) is freely slidable endwise in the slot 51 when the locking nut 78 is loosened.

In order to avoid weakening the blade Iiiby the provision of another locking groove, like the groove 62, in its other side, such other locking groove is omitted and is not required for locking the blade in a reversed position in the slot 5%. Instead, the blade 10 can be removed from the slot 5% the position of the screw 64 reversed by rotating the same, so as to put the detent at the opposite side of the blade, and thereat engaged in the locking groove 62.

The locking screw 6 turns in a radial bore 65 in the block 4'9, which is centered relative to and is larger in diameter than the slot Stt.

For frictionally locking the turntable 2b in a selected rotated position relative to the blade 19 and the block 40, there are located on a diameter of the block 40, a pair of diametrically spaced locking screws 8t}, 82 which are threaded in bores 84, 86, respectively, provided as seen in FIGURE 3, through the block 4% and opening to the side 52 of the slot 5t? and to the face side 88 of the block. The screws Si), 82 have knurled heads 91 92 sufiiciently large to bear against both the block side 88, and the face side 32 of the plate 22, when tightened, so as to frictionally lock the plate 22 and the block 40 against rotation relative to each other. Compression washers 94 are provided on the screws between their heads and the block and plate sides.

The face side 16 of the blade Iii is provided along its opposite edges with reversed and coextensive linear scales 96, 93 which preferably have similar inch graduations. The face side 32 of the plate 22 is provided along its edges 26 and 28 with similar degree scales 1th), 102 Whose angled radial graduations 104 reach from opposite sides of perpendicular ninety degree graduation 106,

these graduations intersecting at the center of the block 40. A pair of outer and inner concentric circular ninety degree protractor scales 108, are provided on the face side of the plate 22 having major divisions of ten degrees and minor divisions of one degree. The turntable 2G is rotatable through three hundred and sixty degrees. As seen in FIGURE 1, the protractor scales are similar but are reversed with respect to each other, with the zero mark 212 of the inner scale aligned with the one hundred and eighty degree mark 114 of the outer scale. As seen in FIGURE 1, when the turntable 29 is rotated relative to the blade 10 to a position in which the turntable base line 35 is coincident with the edge 14 of the blade 10, the edge 26 of the turntable will be disposed at an angle of fifteen degrees to the edge 12 of the blade It), and the edge 28 of the turntable at an angle of thirty degrees to the blade.

For additional uses of the above described device other than those afforded by the described scales, the blade can have other scales and protractor markings, such as for rafter pitches, polygonal angles on its reverse side, the blade then being reversible in the slot 50, as required by the work to be done, as above described.

It will be understood that with an edge of the blade applied to a surface, various angles relative thereto are quickly and easily and accurately obtainable by rotating the turntable 20, so as to relate turntable scales and protractor scales to edges of the blade.

Although there has been shown and described herein a preferred form of the invention, it is to be understood that the invention is not necessarily confined thereto, and that any change or changes in the structure of and in the relative arrangements of components thereof are contemplated as being within the scope of the invention as defined by the claims appended hereto.

What is claimed is:

1. A bevel protractor comprising a block having face and reverse side and a peripheral edge, said block being formed with a slot spaced from said sides and having an open side and open ends and a bottom, an elongated blade sliding endwise through said slot and bearing upon the slot bottom, first locking means for locking the blade in endwise adjustments in the slot, a protractor plate rotatably mounted on the block at the face side of the block, said protractor plate having a base side coinciding with the bottom of said slot and having differently angled edges related to the base side, said protractor plate reaching across said blade with its angled edges at opposite sides of the block and second locking means on the boss protractor plate and engageable with said block and the plate for locking the protractor plate in adjusted positions relative to the block and the blade, said block having a radial bore larger in diameter than and centered relative to the slot and extending through the slot and the slot bottom, said first locking means comprising a locking screw freely rotatable in said bore, said screw having an offset pin on one end positioned between one side of the blade and a related side of the slot, said one side of the blade being formed with a longitudinal locking groove and said pin having a lateral detent engaged in the groove, and a nut threaded on said screw and bearing against a part of the block for drawing the screw in the bore for clamping the blade between the detent and the bottom of the slot, said blade being reversible in the slot with the locking screw turned in said bore and with said pin positioned between the said related side of the slot and said other side of the blade.

2. A bevel protractor comprising a block formed with a slot spaced from its sides an elongated blade extending lengthwise in said slot and bearing upon its bottom, first means for locking the blade in the slot in lengthwise adjusted positions, a circular boss on a side of said block having a free end, a protractor plate having a circular opening receiving said boss, said first locking means comprising a nut and said block and said boss having an opening exposing said nut, and screws threaded in the boss at opposite sides of said circular opening, said screws having enlarged diameter heads adapted to bear against the side of the protractor plate remote from the block and the free end of the boss to hold the protractor plate in a rotated position relative to the block and the blade.

3. A bevel protractor comprising a block formed with a slot spaced from its sides and opening to opposed edges thereof, an elongated blade extending through the slot and beyond the opposed edges of the block, said slot having a bottom upon which said blade rests, first locking means for locking the blade in adjusted lengthwise positions in the slot, a circular boss on one side of the block, a rotatable protractor plate formed with a circular opening receiving said boss, and second locking means for locking the protractor plate in rotated positions relative to the block, said second locking means being carried by the boss and engageable with the protractor plate.

4. A bevel protractor comprising a block formed with a slot spaced from its sides and opening to opposed edges thereof, an elongated blade extending through the slot and beyond the opposed edges of the block, said slot having a bottom upon which said blade rests, first locking means for locking the blade in adjusted lengthwise positions in the slot, a circular boss on one side of the block, a rotatable protractor plate formed with a circular opening receiving said boss, and second locking means for locking the protractor plate in rotated positions relative to the block, said second locking means being carried by the boss and engageable with the protractor plate, said first locking means comprising a bore larger in diameter than and indenting the walls of the slot, said blade having a longitudinal groove in a side thereof, a pin extending longitudinally of the bore between the said side of the blade and the related side of the bore, said pin having a lateral detent engaged in the blade groove, said pin having a screw on the end thereof remote from the detent, said pin being eccentric relative to the axis of the screw, and a nut threaded on the screw and adapted to bear against a part of the block in the region of the bottom of the slot.

5 A bevel protractor comprising a block formed with a slot spaced from its sides and opening to opposed edges thereof, an elongated blade extending through the slot and beyond the opposed edges of the block, said slot having a bottom upon which said blade rests, first locking means for locking the blade in adjusted lengthwise positions in the slot, a circular boss on one side of the block, a rotatable protractor plate formed with a circular opening receiving said boss, and second locking means for locking the protractor plate in rotated positions relative to the block, said second locking means being carried by the boss and engageable with the protractor plate, said second locking means comprising a screw threaded in the boss and having an enlarged head adapted to bear against the boss and the protractor plate.

References Cited in the file of this patent UNITED STATES PATENTS Re. 12,119 Oehrle June 9, 1903 621,177 Sykes Mar. 14, 1899 651,037 Hawkins June 5, 1900 678,018 McFarland July 9, 1901 759,239 Clark May 10, 1904 1,127,802 Palmer Feb. 9, 1915 1,772,925 Wernicke Aug. 12, 1930 2,104,354 Rich Jan. 4, 1938 

